[libcxxabi] [libunwind] [libunwind][AIX] Handle VAPI-based return addresses in stack unwinding for LLU (PR #209280)

[Jon Roelofs via cfe-commits]

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@@ -1469,6 +1475,30 @@ template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
   static constexpr size_t _EXTRA_LIBUNWIND_FRAMES_WALKED = 5 - 1;
   _registers.returnto(_walkedFrames + _EXTRA_LIBUNWIND_FRAMES_WALKED);
 #else
+#if defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
+  if (isKnownVapiNotActive()) {
+    // If the current frame is known VAPI not active , execute the VAPI return
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jroelofs wrote:

```suggestion
    // If the current frame is known VAPI not active, execute the VAPI return
```

https://github.com/llvm/llvm-project/pull/209280